xcbuild: update meta and comments

pkgs/os-specific/darwin/apple-source-releases/Librpcsvc/default.nix

···
   '';
 
   meta = with stdenv.lib; {
-    description = "";
     maintainers = with maintainers; [ matthewbauer ];
     platforms   = platforms.darwin;
     license     = licenses.apsl20;

pkgs/os-specific/darwin/apple-source-releases/adv_cmds/xcode.nix

···
 { stdenv, appleDerivation, fetchurl, xcbuild, libcxx }:
 
 appleDerivation {
-  # disable pkill from build
+
+  # pkill requires special private headers that are unavailable in
+  # NixPkgs. These ones are needed:
+  #  - xpc/xpxc.h
+  #  - os/base_private.h
+  #  - _simple.h
+  # We disable it here for now. TODO: build pkill inside adv_cmds
   patchPhase = ''
     substituteInPlace adv_cmds.xcodeproj/project.pbxproj \
       --replace "FD201DC214369B4200906237 /* pkill.c in Sources */," ""

pkgs/os-specific/darwin/apple-source-releases/network_cmds/default.nix

···
 
   NIX_CFLAGS_COMPILE = " -I./unbound -I${xnu}/Library/Frameworks/System.framework/Headers/ -D__APPLE_USE_RFC_2292 -DIPV6_DONTFRAG=14 -DINET6";
 
+  # "spray" requires some files that aren't compiling correctly in xcbuild.
+  # "rtadvd" seems to fail with some missing constants.
+  # We disable spray and rtadvd here for now.
   patchPhase = ''
-    # disable spray, rtadvd
     substituteInPlace network_cmds.xcodeproj/project.pbxproj \
       --replace "7294F0EA0EE8BAC80052EC88 /* PBXTargetDependency */," "" \
       --replace "7216D34D0EE89FEC00AE70E4 /* PBXTargetDependency */," ""
···
       install */*.$n $out/share/man/man$n
     done
 
-    mkdir -p $out/etc/
-    install rtadvd.tproj/rtadvd.conf ip6addrctl.tproj/ip6addrctl.conf $out/etc/
+    # TODO: patch files to load from $out/ instead of /usr/
 
-    mkdir -p $out/local/OpenSourceVersions/
-    install network_cmds.plist $out/local/OpenSourceVersions/
+    # mkdir -p $out/etc/
+    # install rtadvd.tproj/rtadvd.conf ip6addrctl.tproj/ip6addrctl.conf $out/etc/
 
-    mkdir -p $out/System/Library/LaunchDaemons
-    install kdumpd.tproj/com.apple.kdumpd.plist $out/System/Library/LaunchDaemons
+    # mkdir -p $out/local/OpenSourceVersions/
+    # install network_cmds.plist $out/local/OpenSourceVersions/
+
+    # mkdir -p $out/System/Library/LaunchDaemons
+    # install kdumpd.tproj/com.apple.kdumpd.plist $out/System/Library/LaunchDaemons
  '';
 
   meta = {

pkgs/tools/misc/contacts/default.nix

···
     cp ./contacts-*/Build/Products/Default/contacts $out/bin
   '';
 
+  ## FIXME: the framework setup hook isn't adding these correctly
   NIX_LDFLAGS = " -F${Foundation}/Library/Frameworks/ -F${AddressBook}/Library/Frameworks/";
 
   meta = with stdenv.lib; {